This invention relates generally to a machine stability system and more specifically to a machine stability system for an articulated work machine that provides an output signal to an output device.
A variety of articulated machines are utilized for construction and excavation work. Examples of this sort of machine are a wheel loader or an articulated truck. A wheel loader may be used to transport heavy loads from one location to another, often encountering a series of turns and varying grade slopes on the route between two or more locations. If the load being carried is quite heavy, the weight of a front portion of the machine and the load may not be adequately offset by the rear portion of the machine, thus causing an unstable condition. This condition may also occur when the wheel loader is picking up a portion of a load from a pile. In these types and similar instances, the stability of the wheel loader may be less than optimal, sometimes causing the rear wheels of the wheel loader to lift from the ground and providing discomfort to the operator. In extreme conditions the wheel loader can tip over.
U.S. Pat. No. 4,284,987, issued Aug. 18, 1981, to Harry G. Gibson et al. (hereafter referenced as ""987) discloses a tip-over warning system for vehicles of the articulated type which utilizes a swing pendulum pivoted in a frame which is mounted on and simulates the stability triangle of the vehicle. The pendulum and frame are connected in an electrical circuit including a current source and an alarm device. When the pendulum touches a side arm of the frame, the circuit is completed, thus energizing the alarm device.
Accordingly, the art has sought a method and apparatus of a machine stability system which: operates reliably; protects the load, machine, and operator from a tip-over; provides operator comfort and acceptability; encourages operator confidence which may lead to more rapid maneuvering and greater productivity; precludes the movement, articulation, or both, of a machine if an instability event occurs; may be used in a timely and efficient manner; and is more economical to manufacture and use.
The present invention is directed to overcoming one or more of the problems as set forth above.
In an embodiment of the present invention, a machine stability system is provided. This system includes a machine, a front sensor system, a rear sensor system, and a controller. The machine is adapted to carry a load. The front sensor system is adapted to produce a front signal indicative of the location of the center of gravity of the load and a portion of the machine relative to a predetermined point. The rear sensor system is adapted to produce a rear signal indicative to the center of gravity of a second portion of the machine relative to the predetermined point. The controller receives the front signal and the rear signal and responsively produces an output signal.
In an embodiment of the present invention, a method of measuring machine stability is provided. This method includes the steps of sensing a front weight and front position and responsively producing a front signal, sensing a rear weight and rear position and responsively producing a rear signal, receiving the front signal and the rear signal, comparing the front signal and the rear signal to predetermined values, and responsively producing an output signal.
In an embodiment of the present invention, a machine stability system is provided. The machine stability system includes a first frame, a second frame, an articulation joint, an articulation sensor, a weight sensor, a position sensor, a controller, and an output device. The articulation joint connects the first frame and the second frame and has an articulation angle. The articulation sensor senses the articulation angle and responsively produces an articulation signal. The weight sensor senses the weight or a load and responsively produces a weight signal. The position sensor senses the position of the load and responsively produces a position signal. The controller receives the articulation angle signal, the weight signal, and the position signal and responsively produces an output signal. The output device receives the output signal.